The present invention relates to a lens-fitted film unit onto which an external member is adhered which covers a boundary portion of the first member and the second member constituting the external surface.
In the conventional lens-fitted film unit, there is a lens-fitted film unit which has the first member and the second member constituting the external surface, and for example, a unit main body housing a mechanical member is covered by a front cover and a rear cover. In such the lens-fitted film unit, it is further covered by a paper made external member bent at the position of a ridgeline of the front cover and the rear cover. This paper made external member covers an unseemly portion of an appearance of the front cover and the rear cover, and a trade name, a simple explanation for use, or the like, is written on it.
A lens-fitted film unit is conventionally known in which an engaging claw is provided on any one side of the front cover and the rear cover, the front cover and the unit main body, or the rear cover and the unit main body, and an engaging hole is provided on the other side so that the front cover and the rear cover are fitted.
Further, as an external member, other than the paper made external member, a label-like external member is also known which is adhered to the front cover or the rear cover. Further, there also be a case in which, in order to reinforce the connection of the front cover and the rear cover, the external member is adhered so that the boundary portion of the front cover and the rear cover is covered. In this case, the external member has a function to make the appearance attractive, and a function to reinforce the connection of the front cover and the rear cover.
However, in the case where the lens-fitted film unit is dropped, there is a problem in which the external member is broken near the boundary portion of the front cover and the rear cover, and after that, the connection of the front cover and the rear cover is not reinforced by the external backing body.
As the result of various consideration, the following is found: in the external member, there is an external member in which a crack or tear is caused independently of its direction, and an external member having a direction in which it is easily cracked or torn, and a direction in which it is hardly cracked or torn depending on the direction. Further, it is found that the crack or tear is easily caused on the external member when it is dropped, in the case where the direction in which it is easily cracked or torn coincides with the direction of the boundary portion of the front cover and the rear cover. Further, when the direction in which the external member is easily cracked or torn, is crossed with the direction of the boundary portion, the crack and tear of the external member caused by dropping the lens-fitted film unit can be prevented.
The lens-fitted film unit by which the customer completes picture-taking, and which is sent to the photofinishing lab, is collected by the manufacturer and recycled. In this case, in the conventional lens-fitted film unit which is covered by the paper made external member which is bent at a position of ridgeline of the front cover and the rear cover, or by the label-like external member made of material different from the front and rear covers, the front and rear covers are made of resins, and its material is different from that of the external member, and therefore, the lens-fitted film unit can not be pulverized at recycling, and the external member is removed. However, it requires a large number of man-hours, resulting in an increase of cost. Accordingly, it is considered that the external member is formed of the same material as the front and rear covers. However, in the case where the external member is formed of polystyrene which is recently most commonly used as the material forming the front and rear covers and main body, when the lens-fitted film unit is dropped, cracking of the external member more easily occurs near the boundary portion of the front cover and the rear cover, which is a problem.